SaaS integration guide
Stripe Email Integration for SaaS: 14 Tools, Billing Events, and Safe Implementation
A practical guide to connecting Stripe billing states with SaaS email workflows, comparing 13 tools without assuming native coverage, fixed pricing, or automatic revenue attribution.
Short answer
Keep Stripe authoritative for billing state, normalize only the events your email workflow needs, and choose a delivery or lifecycle tool based on the job. A connector can reduce plumbing; it does not prove attribution, remove consent obligations, or make duplicate events harmless.
Start with the billing event, not the vendor
Stripe email integration usually means one of three things: a transactional message generated by an invoice state, a lifecycle message triggered by a subscription change, or a marketing segment informed by billing context. These have different urgency, consent, ownership, and failure requirements. Treating them as one “Stripe integration” is how receipts end up in a campaign workflow or a recovered customer receives another dunning reminder.
| Stripe event | Possible email job | Safe implementation question | Failure to test |
|---|---|---|---|
| checkout.session.completed | Trial or purchase welcome | Confirm payment state and consent; do not infer entitlement from a click. | Duplicate event, refund, delayed sync |
| invoice.payment_failed | Billing reminder or support task | Use Stripe as source of truth and stop after recovery. | Retries, dunning policy, account owner |
| customer.subscription.updated | Plan or lifecycle message | Map only approved fields and version the event contract. | Plan change race, downgrade, cancellation |
| invoice.paid | Receipt or recovery exit | Suppress pending-payment reminders when the paid event is authoritative. | Webhook order, idempotency, timezone |
14 tools to evaluate
The profiles below are fit hypotheses, not claims that every tool has a native Stripe connector. Follow the official links, confirm current integration documentation and plan rules, and price the complete architecture: vendor, middleware, engineering time, and operational ownership.
| Search intent | Shortlist | Validate first |
|---|---|---|
| Product-led SaaS | Customer.io, Loops, HubSpot | Identity, event latency, activation exits |
| Commerce subscription | Klaviyo, Drip, Brevo | Purchase mapping, refunds, channel consent |
| Transactional service mail | Postmark, Resend, SendGrid | Streams, retries, templates, incident ownership |
| Prototype or handoff | Zapier, Make | Task cost, duplicate handling, rollback |
1. Sequenzy
Sequenzy connects to Stripe via OAuth rather than hand-maintained webhooks: customer, subscription, invoice, and payment state sync automatically, and billing events can directly enroll, advance, or suppress lifecycle sequences. That makes it the shortest path from Stripe truth to dunning, trial conversion, plan-change education, and win-back without a middleware layer.
Native sync does not remove the architecture duties. Keep Stripe authoritative, verify duplicate-event and out-of-order handling, test the recovery exit that stops dunning after a successful retry, and keep receipts and account-critical notices on a separately governed stream when their failure requirements differ.
Best for: SaaS teams that want native Stripe billing state in lifecycle email
Pros: Native Stripe OAuth sync with billing-aware sequences. Cons: Broader CRM and commerce breadth need companion systems.
Pricing caveat: From $19/month; verify current workspace, subscriber, send, automation, and support terms directly with Sequenzy.
Implementation pilot: Connect a test Stripe account, fire payment-failed and recovery fixtures, and verify the dunning exit, suppression, and rollback.
Check Sequenzy official information for current capabilities, integration coverage, limits, and terms.
2. Customer.io
Customer.io fits teams that want Stripe state to become part of a broader product-event model. A payment failure, trial conversion, or cancellation can be evaluated alongside activation and account identity rather than treated as an isolated contact field.
The integration is only as reliable as the event contract. Document Stripe customer-to-user identity, consent, deduplication, retries, and message exits before building branches; confirm which data arrives natively and which must be sent through your own pipeline.
Best for: Event-aware SaaS lifecycle messaging
Pros: Flexible event and identity orchestration. Cons: Needs technical ownership and governance.
Pricing caveat: Verify profiles, messages, events, workspaces, channels, and data-retention assumptions against volume.
Implementation pilot: Process one subscription event family with a holdout and a pause/rollback switch.
Check Customer.io official information for current capabilities, integration coverage, limits, and terms.
3. HubSpot Marketing Hub
HubSpot is useful when billing state must reach sales and customer-success owners. Stripe events can inform lifecycle stage, task creation, or a carefully scoped customer message while the CRM remains the place operators review account context.
Do not assume a connector supplies every invoice or subscription object your team needs. Test field mapping, duplicate contacts, consent, owner handoffs, and what happens when a customer changes plan twice before the workflow runs.
Best for: CRM-connected billing follow-up
Pros: Shared CRM context and operational handoffs. Cons: Suite complexity and contact economics.
Pricing caveat: Model marketing contacts, seats, required hubs, automation, onboarding, and integration work; request a current quote.
Implementation pilot: Route one failed-payment state to a test owner and verify suppression after recovery.
Check HubSpot Marketing Hub official information for current capabilities, integration coverage, limits, and terms.
4. ActiveCampaign
ActiveCampaign suits teams that need conditional follow-up around billing events without making every workflow a custom application. Tags, fields, waits, and goals can express a small dunning or win-back program when the data feed is stable.
Its flexibility can create hidden state. Name the Stripe event source, define exits for payment recovery and cancellation, and test repeated webhooks so a subscriber cannot enter the same sequence twice.
Best for: Branching dunning and customer follow-up
Pros: Accessible branching and automation controls. Cons: Tag and state governance can become difficult.
Pricing caveat: Check contacts, seats, automation bundles, integrations, and current tier limits.
Implementation pilot: Replay success, failure, recovery, and cancellation fixtures against one workflow.
Check ActiveCampaign official information for current capabilities, integration coverage, limits, and terms.
5. Brevo
Brevo is worth testing when Stripe context will support both marketing segmentation and service-adjacent messaging under one account. Send-based economics may suit infrequent campaigns, but the billing workflow still needs a clear source of truth.
Keep receipts and promotional dunning logically separate, even if the vendor hosts both. Confirm webhook or connector coverage, sender authentication, bounce handling, and whether a recovered payment immediately suppresses the next reminder.
Best for: Cost-conscious teams needing marketing and transactional streams
Pros: Broad email surface and multiple pricing dimensions. Cons: Stream boundaries and channel costs need care.
Pricing caveat: Separate contact, send-volume, automation, transactional, SMS, and overage rules.
Implementation pilot: Test one billing reminder and one marketing segment with separate suppression rules.
Check Brevo official information for current capabilities, integration coverage, limits, and terms.
6. Mailchimp
Mailchimp can work when Stripe is used to place contacts into a few clear states such as trial, active, or canceled. It is a reasonable editorial and campaign layer when the billing logic has already been normalized elsewhere.
Avoid presenting a custom sync as native billing intelligence. Test the sync delay, field definitions, unsubscribe behavior, exports, and the limit of the data needed for dunning; complex invoice logic may belong in an application workflow.
Best for: Generalist teams with light billing segmentation
Pros: Familiar campaign operations and ecosystem. Cons: Billing depth depends on the integration path.
Pricing caveat: Model billable contacts, sends, seats, automation gates, and connector or middleware cost.
Implementation pilot: Sync three normalized states and verify one message exit per state.
Check Mailchimp official information for current capabilities, integration coverage, limits, and terms.
7. Klaviyo
Klaviyo is a candidate when Stripe payments sit beside commerce behavior, catalog data, or subscription purchases. The useful question is whether payment state improves a customer journey that already depends on purchase or product context.
SaaS teams should validate the data model before assuming commerce terminology maps cleanly to recurring subscriptions. Test recent-payer suppression, refunds, consent across channels, and whether reported revenue is attributed or incrementally measured.
Best for: Commerce subscriptions and purchase-aware messaging
Pros: Rich commerce and purchase segmentation. Cons: Potentially unnecessary complexity for pure SaaS billing.
Pricing caveat: Forecast profiles, email, SMS, catalog, and consent separately; confirm Stripe coverage for your objects.
Implementation pilot: Compare a payment-state segment with a recent-purchase holdout.
Check Klaviyo official information for current capabilities, integration coverage, limits, and terms.
8. Drip
Drip makes sense when Stripe billing events are part of a commerce-style customer lifecycle: purchase, renewal, failed payment, and reactivation. Its strength is the marketing workflow around a transaction rather than invoice accounting itself.
Verify the exact Stripe path and supported event fields. A workflow that only knows a purchase occurred cannot safely stand in for plan status, invoice state, or entitlement logic; keep those decisions in the billing system.
Best for: Commerce-led subscription journeys
Pros: Commerce-oriented lifecycle automation. Cons: Coverage and SaaS billing semantics require validation.
Pricing caveat: Confirm subscriber tiers, email volume, integrations, and current ecommerce features.
Implementation pilot: Test renewal and failed-payment events with a stop rule after recovery.
Check Drip official information for current capabilities, integration coverage, limits, and terms.
9. Kit
Kit is a fit for creator businesses where Stripe-backed purchases should change newsletter or sequence eligibility. It keeps the editorial relationship central while allowing a small number of buyer and non-buyer paths.
It is not a general billing ledger. Confirm how refunds, multiple products, cancellations, and consent changes are represented, and keep fulfillment or account-service messages in a system with the necessary guarantees.
Best for: Creators selling subscriptions or products through Stripe
Pros: Creator-friendly audience and commerce workflow. Cons: Limited fit for complex SaaS entitlements.
Pricing caveat: Check subscribers, automation, commerce terms, transaction fees, and supported integrations.
Implementation pilot: Run one paid-offer sequence with buyer suppression and refund testing.
Check Kit official information for current capabilities, integration coverage, limits, and terms.
10. Loops
Loops is worth considering when a small SaaS team wants product-triggered email with a focused operating surface. Stripe events can be normalized into trial, active, past-due, and canceled states before entering a modest lifecycle workflow.
Confirm whether the required Stripe connector exists or whether your application must call an API. Keep event ownership, retries, suppression, and audit logs in your integration layer rather than relying on an ambiguous field update.
Best for: Lean SaaS product and transactional email teams
Pros: Lean product-email workflow. Cons: Required Stripe coverage may need custom work.
Pricing caveat: Verify current contacts, sends, event limits, API access, and plan gates.
Implementation pilot: Send one API-mapped billing event to a test workspace and replay it safely.
Check Loops official information for current capabilities, integration coverage, limits, and terms.
11. Resend
Resend is appropriate when Stripe events should produce application-owned emails such as payment-failed notices, receipts, or entitlement changes. Code review and delivery logs can sit close to the service that decides what the customer is allowed to receive.
It is not a full campaign database or segmentation system by default. Separate promotional messaging, implement idempotency and webhook verification, and make unsubscribe and preference rules explicit before adding marketing use cases.
Best for: Developer-owned billing notifications
Pros: API control and developer observability. Cons: Audience and campaign operations need companion tooling.
Pricing caveat: Check volume, domains, API, team, support, and current plan limits.
Implementation pilot: Verify one invoice event, signed webhook, retry, duplicate, and rollback path.
Check Resend official information for current capabilities, integration coverage, limits, and terms.
12. Postmark
Postmark belongs in a Stripe architecture when service mail must remain distinct from campaigns: receipts, payment-failure notices, and account alerts have different urgency and failure handling from newsletters.
Use it as a delivery component, not as the billing decision-maker. Stripe should remain authoritative for invoice and subscription state; test stream separation, bounces, webhooks, and the handoff to a marketing system.
Best for: Reliable transactional streams beside marketing
Pros: Clear transactional separation. Cons: Not a newsletter or dunning strategy platform.
Pricing caveat: Confirm message-stream, volume, add-on, support, and retention terms.
Implementation pilot: Move one receipt stream and verify delivery events without touching marketing sends.
Check Postmark official information for current capabilities, integration coverage, limits, and terms.
13. SendGrid
SendGrid can serve teams that want a broad delivery layer for billing notifications and, separately, marketing operations. It is useful when application code or an integration service owns the Stripe event mapping.
The platform does not remove the need to design entitlement and consent logic. Confirm which product handles contacts, suppression, templates, event retention, and retries, and avoid treating delivery reporting as proof that an email caused revenue.
Best for: API or SMTP delivery at varied volumes
Pros: Flexible delivery options and APIs. Cons: Architecture responsibilities remain with the team.
Pricing caveat: Separate email API, marketing contacts, automation, dedicated infrastructure, and support pricing.
Implementation pilot: Send a test receipt and dunning notice through separate streams with signed events.
Check SendGrid official information for current capabilities, integration coverage, limits, and terms.
14. Zapier
Zapier can be a useful prototype when a team needs to prove that a Stripe event can reach a contact, task, or small email workflow before investing in a service. It makes the first integration visible to non-engineers.
It is a poor place for high-stakes billing state unless retries, duplicates, privacy, and failure ownership are understood. Use it to validate a narrow workflow, then decide whether volume and correctness justify a durable integration.
Best for: Low-volume prototypes and operational handoffs
Pros: Fast proof of concept and visible handoffs. Cons: Task cost, latency, and retry semantics can limit production use.
Pricing caveat: Check tasks, premium apps, polling or webhook behavior, paths, and current plan limits.
Implementation pilot: Run a low-volume test with duplicate events and a manual stop control.
Check Zapier official information for current capabilities, integration coverage, limits, and terms.
15. Make
Make is useful when the Stripe-to-email workflow needs visible transformation steps: normalize a plan, look up a contact, branch on invoice status, and write an audit record. That can help a small team learn the shape of an integration before codifying it.
Visual mapping still needs engineering review for signatures, secrets, idempotency, backfills, and personal-data minimization. Do not let a scenario become the only record of why a customer received a billing message.
Best for: Inspectable multi-step integration prototypes
Pros: Transparent multi-step transformation. Cons: Operational reliability and governance need deliberate review.
Pricing caveat: Verify operations, execution frequency, data transfer, premium apps, and team limits.
Implementation pilot: Process a fixture set and record every branch, retry, duplicate, and failure.
Check Make official information for current capabilities, integration coverage, limits, and terms.
Stripe architecture checklist
| Layer | Decision | Evidence to retain |
|---|---|---|
| Source | Stripe remains authoritative for customer, invoice, and subscription state. | Event contract, object IDs, signature verification. |
| Identity | Map Stripe customer IDs to an approved user or account key. | Mapping rule, collision test, privacy review. |
| Delivery | Separate service, lifecycle, and promotional streams where risk differs. | Stream policy, suppression rule, owner. |
| Measurement | Distinguish delivery, click, conversion, and incremental effect. | UTM scheme, attribution window, holdout design. |
A reversible 14-day pilot
- Choose one billing use case: recovered payment reminder, trial conversion, or plan-change education. Write the consent and suppression rule first.
- Use a test Stripe account or synthetic fixtures. Verify signed webhooks, idempotency, retries, out-of-order events, and a manual kill switch.
- Compare two tools using the same normalized event payload. Keep receipts and promotional messages in separate streams.
- Measure delivery, complaints, unsubscribes, recovery or activation, operator time, event latency, and full cost. Do not call clicks “revenue” without a documented attribution method.
- Keep the current path available until the new workflow passes recovery, cancellation, refund, export, and rollback checks.
For adjacent decisions, read the transactional-versus-marketing guide, email deliverability guide, and email-tool selection guide. For a broader shortlist, see best broadcast tools for small teams before selecting a connector or API.
Bottom line
The right Stripe email integration is the smallest architecture that preserves billing truth, customer control, and diagnosable delivery. Start with one event and one outcome, verify the official connector or API path, and expand only after duplicates, recovery, consent, and rollback are boring. SaaS teams that want the shortest such architecture should pilot Sequenzy at $19/month first: native Stripe OAuth sync feeding billing-aware sequences, with the same recovery-exit and stream-separation tests applied before anything touches production mail.
Decision snapshot: who is this tool for?
Readers resolve this topic differently based on list size, team stack, budget, and the revenue model behind the sends. The table below compresses the page into the trade-offs that most often decide the outcome. Pricing notes hedge what changes frequently in email marketing; verify the exact figures on each vendor's official pricing page before committing.
| Situation | Better fit | Why |
|---|---|---|
| SaaS or subscription on Stripe, Paddle, or Lemon Squeezy | Sequenzy | Native billing triggers plus revenue attribution; pay-per-send from $19/mo with unlimited contacts |
| Newsletter creator with a modest list | beehiiv / Substack / Buttondown | Publishing-first tooling and growth mechanics for editorial work |
| Very high volume, developer-owned sends | Amazon SES / SendGrid / Resend | API-first infrastructure and per-message economics |
| Ecommerce operator wanting journey automation | Klaviyo / Drip | Store-event journeys driven by browse, cart, and purchase |
| Small budget, general marketing automation | MailerLite / Moosend / Brevo | Approachable editors and reasonably priced entry tiers |
| Deep branching with sales pipeline or CRM | ActiveCampaign / HubSpot / Customer.io | Advanced branching and data-attached automation |
Reader FAQ
Will any of these tools guarantee inbox placement?
No provider can promise inbox placement. Deliverability is a shared result of your domain reputation, list hygiene, consent quality, cadence, and the receiving systems' independent decisions. Better tooling changes the margin you have to work with, not the ceiling.
How should a small team pilot without overspending?
Run a one-month pilot on the real audience: your actual campaigns, one lifecycle trigger if that matters to your model, and one deploy path end to end. Hidden cost is usually operational — setup, integrations, governance — not the sticker contact tier. Timebox it so you can make a decision on data rather than on gut feelings.
Which pricing mistakes trip most people up?
Three: evaluating the entry tier while forgetting the band you will occupy in month 6; forgetting inactive-contact rules that quietly inflate contact counts on some plans; and adding seats as the team grows. Verify current pricing on the official pages during the pilot, then re-audit annually.
Your first 30 days: a practical rollout plan
| Period | What to do |
|---|---|
| Days 1-3 | Write the actual job description for the email program and verify current pricing directly on the official tiers. |
| Days 4-7 | Set up the platform: domain warming, list hygiene, suppression policy, signup form, and one welcome automation. |
| Days 8-14 | Send first real broadcasts; measure deliverability, segmentation behavior, and report quality against edge cases. |
| Days 15-21 | Build one revenue lifecycle journey (trial, dunning, win-back, or post-purchase) and measure completed paths, not opens. |
| Days 22-27 | Test failure modes: bounces, unsubscribes, duplicate submissions, and what the reports really show. |
| Days 28-30 | Reassess cost, deliverability, governance fit, and billing/CRM integration; decide to scale or run a second pilot. |
Advisory note: vendor prices change frequently. Re-verify live pricing on each official page before a purchase decision.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.
Additional considerations before you pick
Pricing bands change frequently in email marketing. Before you commit, open each finalist's official pricing page and re-verify the contact band, send limits, seat rules, and feature gates for your month-6 volume — not the entry tier. Keep the pilot reversible: export contacts, campaigns, and consent history first, set up SPF, DKIM, and DMARC in parallel on both platforms, and document every active broadcast or lifecycle journey before cutting anything over.
| Pricing factor | What to verify |
|---|---|
| Contact band, month 6 | The tier you actually occupy, not the entry tier |
| Send limits at that band | Check overage terms and throttling |
| Seats and add-ons | Confirm which features are gated per tier |
Is there a lower-risk way to start?
Yes: keep the incumbent running during the pilot, sign monthly rather than annual, and verify the exit path in writing. If pricing, support, or deliverability shift mid-pilot, a documented exit path protects you from a bad long-term commitment.
What kills migrations in practice?
Three things: lost consent history, broken lifecycle triggers, and missing suppression list synchronization. Document these three before migrating anything; they decide whether the switch is boring or expensive.